Aegis, the UK media buying group, yesterday reported a strong underlying pre-tax profit boost of 15.4% to £56.2m in the first half of 2008, and said it expected full-year results at the "upper end" of expectations despite the slowing market.

The group, whose subsidiaries include media buying agency Carat, digital network Isobar and research firm Synovate, posted a 13.7% increase in revenue compared with the equivalent period last year to £607.6m on a constant currency basis.

Analysts had been forecasting revenues of around £580m. Underlying operating profit rose 16.7% on a constant currency basis to £65m, while the profit margin rose from 9.7% to 10.7% year on year. Aegis said the results had been driven by solid organic growth, the rise of emerging markets, strategic acquisitions and a 13% strengthening of the euro against the pound, which benefited its operations in mainland Europe. Exchange rate effects contributed £35.5m to the company's £607.6m revenue.

Despite the solid results, Aegis aired a note of caution for the future. "We achieved these results despite a trading environment that is becoming tougher - with signs of slowing demand, particularly in Spain, the US and the UK," said the chief executive, Robert Lerwill. "Consequently our revenue outlook for the second half of 2008 is less certain."

He said Aegis anticipated a lower rate of market growth in the second half of the year and was therefore "taking some early steps to tighten our cost base in a number of markets ... Nonetheless we remain confident of delivering a result for the year at the upper end of market expectations."

The company said 29% of revenue at Aegis Media came from digital operations, up from 26% in 2007.